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| n | a(n) |
|---|---|
| 1 | 5 |
| 2 | 16 |
| 3 | 40 |
| 4 | 455 |
| 5 | 1650 |
| 6 | 10706 |
| 7 | 76068 |
| 8 | 445597 |
| 9 | 2902533 |
| 10 | 19204880 |
| 11 | 121652513 |
| 12 | 790850405 |
| 13 | 5141909319 |
| 14 | 33135126906 |
| 15 | 214855459081 |
| 16 | 1392224798269 |
| 17 | 9005556603052 |
| 18 | 58337331135135 |
| 19 | 377789663876767 |
| 20 | 2445748153198451 |
[5,16,40,455,1650,10706,76068,445597,2902533, 19204880,121652513,790850405,5141909319, 33135126906,214855459081,1392224798269, 9005556603052,58337331135135,377789663876767, 2445748153198451] |